The roles of surface wettability and roughness of carbon fibers in interfacial enhancement of silicone resin composites

Besides chemical bonding, surface wettability and roughness of carbon fibers (CFs) also play key roles in improving interfacial adhesion of CFs composites. In this study, the roles of surface wettability and roughness of CFs in interfacial enhancement of methylphenylsilicone resin composites were systematically studied. p‐Phenylene trimethoxyaminosilane (PTMAS) was chemically grafted onto CFs to increase surface polarity and wettability. Furthermore, by bridging PTMAS, the bigger surface roughness of fibers was obtained after following epoxycyclohexyllsobutyl‐polyhedral oligomeric silsesquioxanes (POSS) grafting. PTMAS grafting (CF–PTMAS) had higher wettability and surface energy than that of the grafting with PTMAS and further with POSS (CF–PTMAS–POSS). However, surface roughness of CF–PTMAS was lower than that of CF–PTMAS–POSS. Interfacial shear strength and interlaminar shear strength showed great enhancements, especially for CF–PTMAS–POSS composites, indicating that surface roughness played more important role than the wettability for interface improvement. Additionally, antihydrothermal aging behaviors were also improved obviously. POLYM. COMPOS., 40:E255–E264, 2019. © 2017 Society of Plastics Engineers